Our projects

Our projects

Berry group

Quantum simulations and algorithms

Our research is in the areas of quantum information and quantum optics. In quantum information, we are performing research into the most efficient ways of simulating physical quantum systems on a quantum computer. Such simulations are a very promising application for quantum computers, because simulating
quantum systems is extremely important in areas such as design of molecules, and it is natural for quantum computers to give exponential speedups.

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Our research has shown how to perform simulations far more efficiently than the traditional product formula approach, and we are now researching the specific
application of these techniques to quantum chemistry.

In the area of quantum optics, we are researching the most accurate ways to perform phase measurements. Phase measurements are needed for precision measurement, for example in gravitational wave detection. While coherent states as produced by a laser give one level of precision, special nonclassical
states such as squeezed states or “NOON” states can potentially give much higher precision. Our research shows how to best perform measurements optimised for loss, how to resolve ambiguities in phase measurements arising from use of nonclassical states, and how to best use nonclassical states
for tracking of a varying phase.

Brennen group

Quantum Many Body science

Nature is a wondrous place and it’s not a finished product. I grew up in Alaska and received my PhD in theoretical physics from the University of New Mexico under the advisement of Prof. Ivan Deutsch. Following post-doc positions at NIST Gaithersburg/UMaryland, and the Institute for Quantum Optics
and Quantum Information in Austria I assumed an Assoc. Prof. position at Macquarie in 2007.

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My main interests are how to use physical laws we know, particularly quantum mechanics, to probe in ever more exquisite detail the manifestations of nature — from elementary interactions to the collective
behaviour of complex many particle systems. With new engineered quantum systems we can build quantum enhanced sensors like magnetometers and gravimeters to full bore quantum computers that open up entirely new playgrounds of exploration.

Brown group

Biological Quantum science

In recent years, nanodiamonds (< 100nm in size) have emerged from primarily an industrial and mechanical applications base, to potentially underpinning sophisticated new technologies in quantum science and biology. In addition to their chemical and physical stability,
nanodiamonds have color centres whose properties make them attractive bio-labels for imaging and tracking.

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The bright and stable photoluminescence, as well as the straightforward surface functionalisation for targeting to biological structures, has allowed us to begin to probe cellular processes down to the single-molecule scale; one
of the primary goals of biomedical science and, ultimately, therapeutics.

Research in our group is focused on developing methods to process detonation nanodiamonds to use for the imaging and tracking of targeted biomolecules in complex biological systems. This includes research on the processing and characterising of small nanodiamonds with color centres (~4 to 30nm), as
well as controlling and tailoring their surface chemistry, for use in biological environments and quantum nanotechnologies. We are exploring applications ranging from using nanodiamonds as superior biological markers to, potentially, developing novel bottom-up approaches for the fabrication of hybrid
quantum devices that would bridge across the bio/solid-state interface.

Mildren Group

Diamond Optics, Lasers and Quantum Systems

The tightly-bound, highly symmetric and dense lattice that is diamond provides an excellent substrate for investigating a range of extreme optical phenomena. The mostly experimental group focuses on the nonlinear optical properties of the bulk and surface with a firm view towards research translation to applications. Recently, we have a new thrust to exploit diamond’s particular Raman-tensor symmetry to form the basis for a novel source of quantum randomness.

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We have developed a novel approach that simultaneously exploits the symmetry and Raman laser characteristics of Group IV crystals (in this case diamond) to produce low-noise quantum random numbers, with single shot byte readout and potentially on chip and with exceptionally high rates. By aligning
the polarisation of a pump to the [011] lattice direction, two degenerate Raman modes are addressed to yield a random output polarisation. The scattered photon sets off a cavity-enhanced “avalanche” of near-identical photons that can be detected with conventional optics and light detectors.

Members

Robert Williams

Ondrej Kitzler

Chris Baldwin

Mojtaba Moshkani

Zhenxu Bai

Doug Little

Sergei Antipov

Collaborators

Alexei Gilchrist

David Spence

James Downes

Alumni

Aaron McKay (now at Finisar Pty Ltd)

Alex Sabella (DST Group)

Ondrej Kitzler

Hadiya Jasbeer

Soumya Sarang

Matthew Clarke

Publications

Steel group

Integrated Nonlinear Quantum Photonics

While the discipline of quantum optics is 50 years old, the past 5 years has seen a revolution as quantum experiments involving photons have moved from bulk optics with lenses and mirrors into integrated photonic circuits. Chip-based technologies allow us to incorporate dozens of optical
components into solid state devices of just a few square centimetres. This transition is key to harnessing photons for applications in quantum information including secure communication, ultra precise metrology, quantum computing and fundamental tests of quantum mechanics.

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Our research addresses these challenges at the interface of nonlinear photonics and quantum optics. Our theory program studies the basic physics and design of on-chip sources for making non-classical states of light through nonlinear processes involving random fluctuations of the quantum vacuum, as well as complex circuits for multiphoton quantum
walks and other quantum processing. In the laboratory, we are using waveguide writing by high power femtosecond lasers to develop both photon light sources and three-dimensional circuits that are completely contained in single chips of glass. We have research student opportunities for
mathematically-inclined theorists, highly practical experimentalists and people anywhere in between.

Terno group

Fundamental Quantum information

Quantum theory and general relativity are often described as the two pillars of modern physics; this metaphor is apt in more than one way. The two theories are built on different foundations— probabilities that evolve in time cannot be easily reconciled
with a deterministic unfolding of events in a dynamical spacetime.

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Their various aspects are verified with a spectacular precision on scales ranging from cosmic distances to fractions of a millimeter in the case of gravity and from 10^−19 m to 143 km for quantum mechanics, but almost exlusively in separate regimes.

The unification of quantum theory with gravity is perhaps the biggest open problem of theoretical physics. Such a theory is not only needed for logical reasons (part of our research is to understand them better!), but also for the understanding the early Universe, the final fate of black holes, and
arguably the very structure of space and time. This is an old problem, almost as old as quantum mechanics itself.

Information theory, and the advances of quantum information in the last thirty or so years form the background of our research. It deals with complexity of physical process, relativistic quantum information, quantum foundations, precision tests of relativity, effects of quantum gravity and black hole
physics. The common theme of this research is that information is physical. Its processing is a branch of physics, while study of physics involves the study of information. The technical cohesion follows from a central role of quantum correlations and a variety of entropy-like quantities that are used
to characterize them.

Twamley group

Hybrid Quantum science

Twamley’s theory research focuses on investigating hybrid quantum systems where one considers connecting up a variety of different types of quantum sub-systems which, when taken together, can reveal new physics or perform new functions, beyond that of the individual sub-systems.

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An example of
an hybrid system is a design that joins together photonic, superconducting and solid-state (diamond) sub-systems, to connect up via an optical fibre, distant superconducting quantum computers. Another example it to connect up electronic and vibrational sub-systems to design one-way directional quantum
wires for electrons. The field of hybrid quantum engineering covers many sub-topics including, optomechanics, superconductors, solid-state quantum devices, optimal quantum control, quantum error correction, algorithms and simulation.

Volz group

Quantum Materials

The Quantum Materials and Applications (QMAPP) group focuses on cross-disciplinary research activities in quantum physics, nanotechnology and material science. With state-of-the-art facilities located at Macquarie University and CSIRO, Lindfield, we are part of the ARC Centre of Excellence for Engineered Quantum Systems (EQuS), which is a multi-institutional national
centre whose mission is to study and harness the features of quantum physics for the realisation of future quantum-based technologies.

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In the QMAPP group we specifically study material systems such as nano-diamonds containing defect centres and nanoscale low-dimensional GaAs-based emitters, and explore their potential for quantum-based applications ranging from spin-based quantum information technology, to strongly coupled light-matter
interfaces for non-linear quantum photonics, to high-resolution single-spin sensing both for exploring other novel quantum materials at low temperatures and for potential biomedical applications.